Dental protheses, jaw-splints and jacket-crowns



July 24, 1956 P. BRANDAU DENTAL PRoTHEzsEs, JAW-SPLINTS AND JACKET-moms A Filed Feb. 5, 195s -ished work also without substantial benefit.-

United States Patent O y to Union Broach Company,.New York,N. Y.a corporation of New York Application February 5,1953, Serial-'No'.l 3353232 3 Claims. (Cl. 152-2)- The'present invention relates to dental. protheses, jawsplints, jacket-crowns,k andthe like;

There are dental protheses with fillers. for. reinforcement already in the market, suchV llerst consisting, however, of metal webs, whereas at present the material` of the plates isof synethetic. resins, as arule. This. sort of a combination has its disadvantages, however, in sofar as the metal reinforcement-is foreignto the synthetic material, thus preventing anintimate adherence, and-in case of complete sets of artificial teeth, the-metal. was broughtup to the upper edge of thejaw only So-thatthe upper edge of. the gum would still be open to the-risk of beinginjured. A reinforcement to-reach as far as the` gums parts was. not possiblev for technical and cosmetic. reasons. EvenV the best retentionsl of the metal reinforcements would, at their best, result-in only amechanieal lcombination. of adherence but according to expert knowledge in general a metal-fillerwill always remain aforeignsubstance in the finished piece of work-,weakening,the-artificial material andpreventing the resultsfrom being fully satisfactory.

There is another disadvantagedue to the fact-thatthe metal. webs cannot be shaped freelyoi-hand'v but must first be stamped by means ofa die,-,if theyare-to'sfit correctly. Considering .the result inquestion, this-procedure would take far too much time, raising, .the costs :of the-iin- In-A addition, there is the disadvantage of a bad appearance, both cosmetic andesthetic, of the.- fillersiusuallyfmade; of steel, imparting a greyish hue to the rose-tinted synthetic resin. Attempts havebeenmadeto remove`this difficulty by using gilt-steel web. fillers, but these, too, made"thefwork pieces more expensive, and besides, the gilding wore out rather quickly at the open spaces ofthe web in case of a skeleton-prothesis, followed by a fading into'agreyishbrown or even blackish tint; and-beingmost detrimental to the appearance of the finished work. From a mechanical point of view, the grinding-through and polishingthrough of the various wires of the web caused trouble and the tender parts of the mouth were injured.

lf the synthetic resin plate broke, notwithstanding the metal reinforcement, the metal filler caused some difficulty because it was impossible to get the fragments fitted together perfectly, as they tended elastically to move in various directions, so that repair work was most complicated or not at all possible. Furthermore, the use of glass-silk for this purpose had been suggested; however, there is the disadvantage that in case of a rupture the glass-silk would break as well, thus failing to serve as a reinforcement.

In this field the present invention offers an improvement of importance because a reinforcement-filler will be made of a synthetic material having as the base a polyamide or polyurethane, the basic material preferably consisting of a synthetic substance to be polymerized. Such materials are well-known in the eld of plastics. They are formed by condensing an amide with an or- Patented' July:` 24, 1956 2. ganic poly-acid, such-A as hexamethylenediamine with adipic acid, in equimolecular proportions; such-.materials are on-thefmar-ket-in lamentand otherforms under the name of Anylon,; andf -theproduction Athereof isA described in the literature. Similarly-urethane iscondensed Awith an organic poly-acid.v

The new reinforcement-fillermay'either be consistently attached or alsoconnected-to the surrounding plate-material in a less solid-way (mechanical'only). If a vulcanite base-plate isused, the filler consisting of-a nylon network or meshmay be solidly, bonded to the surrounding i/ulcanite by use of any well--known cement; This is true also with reference-to acrylicresinplates, being more compatible with. the tissue,: a material of whichy artificial dentures are madeon aA large scale. With-the jacketcrowns, too, thisvreinforcement-ller results in a` considerably increased strength of the crown and above all any splinteringtof the-jacket-crown will be avoided, increasing its durability` extraordinarily at the same time, whereas as .regards the vsplints a considerable simplification. of the operating/methods will be obtained in addition to increasefof strength. In any,l case,the invention offersthe following advantages:

(l) The new reinforcement-ller-is of` an originv similarto the surrounding-materials, is invisible and elasticallylductile at-thelsame time, so that it cannot be torn topieces. This results'lin ankfextraordinary increase of the strength, including that ofthe base-plate, so that now the base-plate-can. be made. considerably` thinner than previously, facilitating the wearing ofthe artificial-teeth in the mouth to a greatextent. Besides, due to the great stability.y and 4elasticity of' theplate, ysome openingsy may now be left inthe plate, makingl it far easierfto keep in the mouth. If'aa` plate should break, which naturally cannot be completelyavoided, the reinforcement-filler offers' the advantage thata further use of the broken piece will still bepossiblegfor al certain period of time until the repair-work can be-carriedfout.- The repair-work itself is most simple because the elastic freeV bers need only cutting-,throughain-order to have the fragments fixed and dulyrepaired by, means of synthetic resin, fresh reinforcements serving forstrengthening .applied'within the' dovetailsandretentions in. the shape of=ilat.belts, foils, or single bers, the repaired plate thus regaining its previous strength' almost' entirely. y

(2) TheA reinforcement-filler being colorless, any protruding parts of the 'filler willinot beV apparent and the appearancofthe' platewill notbe affected in any way',

A(3) Detofthef'greatelasticityI of reinforcement'- llersthe brittlien'es's of base-plates made of synthetic resin will fber'educed considerably.

(4) The new artificial denture can be made far more easily, no presses or dies being required as would be necessary in the case of metal webs, and much time will be saved. g

(5 Inside of the cavity of the mouth, there will not result any electrolytic currents or other currents detrimental to health, as would be the case with a metal filler getting in touch with saliva or with any other metals in the teeth.

(6) The durability of the dentures, crowns, and splints are considerably increased due to the new filler.

(7) 'The invisibility of the equipment-material allows the mesh-filler to be worked also across the inner edge of the jaw into the gum-parts, which also helps to produce an especially good stabilization.

Furthermore, the invention includes the entire baseplate, jacket-crowns and splints to be produced of synthetic material having the base of polyamide or polyurethane, increasing the number of advantages consid-` erably.

of and in which like reference characters indicate like parts: ,Y

Fig. 1 is a transverse cross-sectional view of a denture or dental prothesis, made'in accordance with ,the present invention; v

Figs. 2 `and 3 are respectively" sideelevational and top plan views of teeth of an individual having splints of the invention applied thereto;

Fig. 4 is an enlarged side elevational view of a pair of teeth having a splint applied thereto;

Fig. 5 is a top plan view of teeth, three of whichk are held in a splint of the present invention, and

Fig. 6 is a vertical cross-sectional view of a crown of synthetic material reinforced by the present invention.

Referring to Fig. l, the base plate a is of a polyacrylic resin, such as of polymerized methyl 'methacrylate On the inner face thereof is a tissue or mesh or fabric of nylon or the like, said tissue being imbedded in plate a before it has become hardened so that the two are intimately combined. Since both substances have practically the same coeiiicient of expansion, the resulting denture is a single unit of high strength` Figs. 2 to 5 illustrate several forms of splints of a type used frequently in dental treatment. Nylon or the like fibers twisted to form threads c are combined with synthetic materials formed by auto-polymerization, whereby rapid production of splints d is obtained. It is applicable to both emergency-splints and permanent bands for fractures of the jaw, replantations of teeth, and of holdingor retention-splints in the orthopaedy of the jaw, when quick action is required.

This is done by placing iigure-eight-shaped `ligatures round the teeth which are to be splinted, using one or more turns or bandages of a laced or twisted nylon thread of diierent thickness.` Following this and for a matter of consolidation, a layer of l or 2 mm. of an auto-polymerizing synthetic material, such as methyl methacrylate, of the same tint of the teeth, as maybe had freely in various forms today, will be applied and slightly shaped, following the line of the nylon thread. The synthetic material hardens, is rough ground after a few minutes and fine polished a little later.

Because of its smooth iinish, the artificial splint is much more attractive in appearance than the hitherto usual wire bindings with their large number of salient hooks. It is less noticeable, being adapted to the tint of the teeth whereas the metal splints are a nuisance to the wearer because of their outstanding appearance.

The technical improvement includes the possibility of a quick production, independent of technically trained staif or laboratory, resulting also in considerable saving of work, no longer requiring casts, patterns, modelling in wax, castings, or bending technics, followed by inserting by means of ementiwhich readily in the.. liquids `of the mouth, so that such metal splints tends Vto dissolve must often be inserted repeatedly or have to be tied up by wire-ligatures, the wire-ends of which cause trouble very often.

The combined synthetic splint as above described, will stick automatically owing to the adhesion of the synthetic material itself, without any additional fastenings. The removing is most simple, just by pulling-od or cutting by means of a separating-disk.

This combination of synthetic material and nylon or the like allows'for a large number of additional results, including the reinforcement of synthetic jacketcrowns-in the shape of rough embossed web-heads f etc. which are put on the stump of a tooth to reinforce the crown` Thus, the splintering of parts of the crown will be avoided and the risk of the crown breaking will be diminished extraordinarily. The head f is placed on the duly prepared stump' of atooth g (Fig. 6) and the synthetic crown, while becoming hard, is placedon top of it as a jacket-crown h, so that the reinforcement f unites with the crown and becomes integral therewith` I claim: 1

l. A dental appliance consisting essentially of a base of a synthetic plastic material taken from the class con sisting of polyamide plastics having imbedded therein a reinforcement iiller made of threads of a `substance taken from the class consisting of polyamide plastics, said illerbeing intimately united with said base.

2. A method of making dental appliances which comprises wrapping around the teeth at least one turn of a thread made of a substance taken from the class consisting of polyamide plastics, applying to said teeth a strip of an autopolymerizable synthetic plastic in contact with said thread, and causing said synthetic plastic to polymerize and to unite with said thread, whereby the splint so formed is strengthened.

3. A method of making dental appliances which comprises placing on a tooth a head made of a substance taken from the class consisting of polyamide plastics, placing over said head a body of an autopolymerizable synthetic plastic, shaping said body to form a crown for said tooth, and causing said synthetic plastic to polymerize and to unite with said head, whereby the crown so formed is strengthened.

References Cited in the file of this patent UNITED STATES PATENTS .2,418,833 Harris et al Apr. l5, 1947 FOREIGN PATENTS 594,579 'Great Britain Nov. 14, 1947 617,605 Great Britain Feb. 9, 1949 

1. A DENTAL APPLIANCE CONSISTING ESSENTIALLY OF A BASE OF A SYNTHETIC PLASTIC MATERIAL TAKEN FROM THE CLASS CONSISTING OF POLYAMIDE PLASTICS HAVING IMBEDDED THEREIN A REINFORCEMENT FILLER MADE OF THREADS OF A SUBSTANCE TAKEN FROM THE CLASS CONSISTING OF POLYAMIDE PLASTICS, SAID FILLER BEING INTIMATELY UNITED WITH SAID BASE. 